Light phenomenon

[Raven]

This is truly a great picture but that's not why I post this.

Is there anyone out there who can explain why the sky "inside" a rain bow tends
to be brighter than on the "outside"? I've seen this on most rainbows both on
photos and in real life.

I guess it has something to to wiht how the light breaks through the waterdrops
but It would be nice to know

[Jipp]

I am not sure that i understand what you mean by brighter insider than outside but I will try that:

Like you guessed (an educated guess, i guess), a rainbow is formed by the refraction (decomposition) of a ray of light by the thousand droplets or water. So, you need water in the air ie. rain or overcast weather -- dark outside and a ray of light piercing through -- bright inside.

So it is one of two things: a hole in the clouds or the sun come from the edge of the cloud.

FYI: You are always standing between the sun and the rainbow that you see. ie the sun is never behind a rainbow.